InputManagerPlatform.cs

using ImGuiNET;
using UImGui.Assets;
using UnityEngine;

namespace UImGui.Platform
{
	// TODO: Check this feature and remove from here when checked and done.
	// Implemented features:
	// [x] Platform: Clipboard support.
	// [x] Platform: Mouse cursor shape and visibility. Disable with io.ConfigFlags |= ImGuiConfigFlags.NoMouseCursorChange.
	// [x] Platform: Keyboard arrays indexed using KeyCode codes, e.g. ImGui.IsKeyPressed(KeyCode.Space).
	// [ ] Platform: Gamepad support. Enabled with io.ConfigFlags |= ImGuiConfigFlags.NavEnableGamepad.
	// [~] Platform: IME support.
	// [~] Platform: INI settings support.

	/// <summary>
	/// Platform bindings for ImGui in Unity in charge of: mouse/keyboard/gamepad inputs, cursor shape, timing, windowing.
	/// </summary>
	internal sealed class InputManagerPlatform : PlatformBase
	{
		private readonly Event _textInputEvent = new Event();
		private readonly KeyCode[] _keyCodes = (KeyCode[])System.Enum.GetValues(typeof(KeyCode));

		public InputManagerPlatform(CursorShapesAsset cursorShapes, IniSettingsAsset iniSettings) :
			base(cursorShapes, iniSettings)
		{ }

		public override bool Initialize(ImGuiIOPtr io, UIOConfig config, string platformName)
		{
			base.Initialize(io, config, platformName);

			return true;
		}

		public override void PrepareFrame(ImGuiIOPtr io, Rect displayRect)
		{
			base.PrepareFrame(io, displayRect);

			UpdateKeyboard(io);
			UpdateMouse(io);
			UpdateCursor(io, ImGui.GetMouseCursor());
		}

		private void UpdateKeyboard(ImGuiIOPtr io)
		{
			// BUG: mod key make everything slow. Go to line
			foreach (KeyCode keyCode in _keyCodes)
			{
				if (TryMapKeys(keyCode, out ImGuiKey imguikey))
				{
					io.AddKeyEvent(imguikey, Input.GetKey(keyCode));
				}
			}

      		// Handle mod keys separately as 2 buttons map to 1 key
			io.AddKeyEvent(ImGuiKey.ModShift, Input.GetKey(KeyCode.LeftShift) || Input.GetKey(KeyCode.RightShift));
			io.AddKeyEvent(ImGuiKey.ModCtrl, Input.GetKey(KeyCode.LeftControl) || Input.GetKey(KeyCode.RightControl));
			io.AddKeyEvent(ImGuiKey.ModAlt, Input.GetKey(KeyCode.LeftAlt) || Input.GetKey(KeyCode.RightAlt));
#if UNITY_EDITOR_OSX || UNITY_STANDALONE_OSX || UNITY_IOS
			io.AddKeyEvent(ImGuiKey.ModSuper, Input.GetKey(KeyCode.LeftCommand) || Input.GetKey(KeyCode.RightCommand));
#else
			io.AddKeyEvent(ImGuiKey.ModSuper, Input.GetKey(KeyCode.LeftWindows) || Input.GetKey(KeyCode.RightWindows));
#endif

			// Text input.
			while (Event.PopEvent(_textInputEvent))
			{
				if (_textInputEvent.rawType == EventType.KeyDown &&
					_textInputEvent.character != 0 && _textInputEvent.character != '\n')
				{
					io.AddInputCharacter(_textInputEvent.character);
				}
			}
		}

		private static void UpdateMouse(ImGuiIOPtr io)
		{
			Vector2 mousePosition = Utils.ScreenToImGui(Input.mousePosition);
			io.AddMousePosEvent(mousePosition.x, mousePosition.y);
			io.AddMouseButtonEvent(0, Input.GetMouseButton(0));
			io.AddMouseButtonEvent(1, Input.GetMouseButton(1));
			io.AddMouseButtonEvent(2, Input.GetMouseButton(2));
			io.AddMouseWheelEvent(Input.mouseScrollDelta.x, Input.mouseScrollDelta.y);
		}

		private static bool TryMapKeys(KeyCode key, out ImGuiKey imguikey)
		{
			static ImGuiKey KeyToImGuiKeyShortcut(KeyCode keyToConvert, KeyCode startKey1, ImGuiKey startKey2)
			{
				int changeFromStart1 = (int)keyToConvert - (int)startKey1;
				return startKey2 + changeFromStart1;
			}

			imguikey = key switch
			{
				>= KeyCode.F1 and <= KeyCode.F12 => KeyToImGuiKeyShortcut(key, KeyCode.F1, ImGuiKey.F1),
				>= KeyCode.Keypad0 and <= KeyCode.Keypad9 => KeyToImGuiKeyShortcut(key, KeyCode.Keypad0, ImGuiKey.Keypad0),
				>= KeyCode.A and <= KeyCode.Z => KeyToImGuiKeyShortcut(key, KeyCode.A, ImGuiKey.A),
				>= KeyCode.Alpha0 and <= KeyCode.Alpha9 => KeyToImGuiKeyShortcut(key, KeyCode.Alpha0, ImGuiKey._0),
				KeyCode.LeftControl => ImGuiKey.LeftCtrl,
				KeyCode.RightControl => ImGuiKey.RightCtrl,
				KeyCode.LeftShift => ImGuiKey.LeftShift,
				KeyCode.RightShift => ImGuiKey.RightShift,
				KeyCode.LeftAlt => ImGuiKey.LeftAlt,
				KeyCode.RightAlt => ImGuiKey.RightAlt,
#if UNITY_EDITOR_OSX || UNITY_STANDALONE_OSX || UNITY_IOS
				KeyCode.LeftCommand => ImGuiKey.LeftSuper,
				KeyCode.RightCommand => ImGuiKey.RightSuper,
#else
				KeyCode.LeftWindows => ImGuiKey.LeftSuper,
				KeyCode.RightWindows => ImGuiKey.RightSuper,
#endif
				KeyCode.Menu => ImGuiKey.Menu,
				KeyCode.UpArrow => ImGuiKey.UpArrow,
				KeyCode.DownArrow => ImGuiKey.DownArrow,
				KeyCode.LeftArrow => ImGuiKey.LeftArrow,
				KeyCode.RightArrow => ImGuiKey.RightArrow,
				KeyCode.Return => ImGuiKey.Enter,
				KeyCode.Escape => ImGuiKey.Escape,
				KeyCode.Space => ImGuiKey.Space,
				KeyCode.Tab => ImGuiKey.Tab,
				KeyCode.Backspace => ImGuiKey.Backspace,
				KeyCode.Insert => ImGuiKey.Insert,
				KeyCode.Delete => ImGuiKey.Delete,
				KeyCode.PageUp => ImGuiKey.PageUp,
				KeyCode.PageDown => ImGuiKey.PageDown,
				KeyCode.Home => ImGuiKey.Home,
				KeyCode.End => ImGuiKey.End,
				KeyCode.CapsLock => ImGuiKey.CapsLock,
				KeyCode.ScrollLock => ImGuiKey.ScrollLock,
				KeyCode.Print => ImGuiKey.PrintScreen,
				KeyCode.Pause => ImGuiKey.Pause,
				KeyCode.Numlock => ImGuiKey.NumLock,
				KeyCode.KeypadDivide => ImGuiKey.KeypadDivide,
				KeyCode.KeypadMultiply => ImGuiKey.KeypadMultiply,
				KeyCode.KeypadMinus => ImGuiKey.KeypadSubtract,
				KeyCode.KeypadPlus => ImGuiKey.KeypadAdd,
				KeyCode.KeypadPeriod => ImGuiKey.KeypadDecimal,
				KeyCode.KeypadEnter => ImGuiKey.KeypadEnter,
				KeyCode.KeypadEquals => ImGuiKey.KeypadEqual,
				KeyCode.Tilde => ImGuiKey.GraveAccent,
				KeyCode.Minus => ImGuiKey.Minus,
				KeyCode.Plus => ImGuiKey.Equal,
				KeyCode.LeftBracket => ImGuiKey.LeftBracket,
				KeyCode.RightBracket => ImGuiKey.RightBracket,
				KeyCode.Semicolon => ImGuiKey.Semicolon,
				KeyCode.Quote => ImGuiKey.Apostrophe,
				KeyCode.Comma => ImGuiKey.Comma,
				KeyCode.Period => ImGuiKey.Period,
				KeyCode.Slash => ImGuiKey.Slash,
				KeyCode.Backslash => ImGuiKey.Backslash,
				_ => ImGuiKey.None
			};

			return imguikey != ImGuiKey.None;
		}
	}
}